Oracle C++ Call Interface Programmer's Guide

Connecting to a Database
Connecting to a Database
You have a number of different options with regard to how your application
connects to the database. These options are discussed in the following sections:
■ Creating and Terminating an Environment
■ Opening and Closing a Connection
■ Creating a Connection Pool
■ Utilizing a Shared Server Environment
Creating and Terminating an Environment
All OCCI processing takes place in the context of the Environment class. An OCCI
environment provides application modes and user-specified memory management
functions. The following code example shows how you can create an OCCI
environment:
Environment *env = Environment::createEnvironment();
All OCCI objects created with the createxxx methods (connections, connection
pools, statements) must be explicitly terminated and so, when appropriate, you
must also explicitly terminate the environment. The following code example shows
how you terminate an OCCI environment.
Environment::terminateEnvironment(env);
In addition, an OCCI environment should have a scope that is larger than the scope
of any objects created in the context of the that environment. This concept is
demonstrated in the following code example:
const string userName = "SCOTT";
const string password = "TIGER";
const string connectString = "";
Environment *env = Environment::createEnvironment();
{
Connection *conn = env->createConnection(userName, password, connectString);
Statement *stmt = conn->createStatement("SELECT blobcol FROM mytable");
ResultSet *rs = stmt->executeQuery();
rs->next();
Blob b = rs->getBlob(1);
cout